Use WriteString instead of Write
Fix section names and section order

See man-pages(7) for more details.
Simplify function parameters
Differentiate between podcasts and feeds
Actually store.Podcasts needs to be a pointer

Otherwise updating podcast.Type and podcast.Latest in main.go is a pain
in the ass.
go fmt
Use appName variable
remove getDirs function
Use MkdirAll instead of Mkdir to create directory used for store
Use XDG_CONFIG_HOME to store the feeds.json file
Use the log package instead of fmt
Simplify return
golint

Implemented a few suggestions by golint <github.com/golang/golint>
Remove -c flag
Identify podcasts by xml url not by title.
Plural
Update flag descriptions
20% cooler
No need to initialize an 'err' variable in main()
Don't panic

Don't confuse users with tracebacks.